Solute–solvent interactions of alkyl acetoacetates in aqueous {1-butyl-3-methylimidazolium bromide [bmim][Br]}ionic liquid solutions in the temperature interval (288.15–308.15) K

• Densities and speeds of sound of alkyl acetoacetates in [bmim][Br].
• Partial molar volumes and compressibility of transfer.
• Apparent molar expansivities and the Hepler's constant were calculated.
• Polar–nonpolar and nonpolar–nonpolar group interactions in alkyl acetoacetates and [bmim][Br].

The density, ρ, and speed of sound, u, of methyl acetoacetate, ethyl acetoacetate in aqueous 1-butyl-3-methylimidazolium bromide solutions have been measured in the temperature interval T = (288.15, 293.15, 298.15, 303.15, and 308.15) K and atmospheric pressure. These data have been used to calculate apparent molar volumes (Vϕ), and apparent molar adiabatic compressibility (Kϕ,s) of these mixtures. The standard partial molar volumes (Vϕ0), standard partial molar volumes of transfer (ΔVφ0), standard partial molar adiabatic compressibility (Kϕ,s0), and standard partial molar adiabatic compressibility (ΔKϕ,s0) of transfer have been determined from these density and speed of sound data. The results have been interpreted in terms of solute-solvent interactions. Later, the temperature dependence of the apparent molar volume was used to calculate apparent molar expansivity ϕE0 and the Hepler's constant values, (∂2Vϕ0/∂T2) to confirm the conclusions obtained from volumetric and speed of sound properties.